This invention relates to a removal system for removing an engine""s used lubricating oil from the engine""s lube oil system throughout engine operation.
It is highly desirable to be able to minimize the amount of service required for internal combustion engines to thereby minimize the interruption in the use of the vehicle/equipment. Degradation and contamination of engine lubricating oil during engine use requires oil changing procedures which account for a significant portion of the maintenance and associated engine xe2x80x9cdown timexe2x80x9d. Conventional periodic oil changes generate an accumulation of waste lubricating oil which must be disposed of and/or processed resulting in undesirable costs. Therefore, extending oil drain intervals and reducing waste disposal are of great value to vehicle/equipment operators.
Consequently, systems have been developed for automatically changing internal combustion engine crankcase oil during engine operation. For example, U.S. Pat. No. 3,447,636 discloses a system for automatically changing engine oil while the engine is operating. The system operates to drain substantially all of the used oil from the engine immediately prior to introducing fresh oil into the engine from a reservoir. The single operation process results in a complete change of the substantially the entire engine oil volume. However, draining the engine prior to refilling with fresh oil necessarily creates a risk that an inadequate supply of lube oil exists in the engine for an interim time period possibly resulting in damage or excessive wear to engine components from insufficient lubrication. Moreover, this system undesirably results in a quantity of waste oil.
Other systems have been developed which automatically change engine lube oil during engine operation while avoiding a waste quantity of oil by directing the used lube oil into the fuel system for burning with the fuel in the engine. These systems periodically drain a small amount of the used oil from the engine lube oil system, and replace the drained quantity with fresh lubricant from an auxiliary tank. For example, U.S. Pat. Nos. 4,869,346 and 5,390,762 to Nelson disclose an automatic crankcase oil change and makeup system including a displacement unit having a piston with a predetermined stroke set to deliver identical, predetermined amounts of fresh oil during each stroke at the same flow rate and volume as the extraction of used oil. The pressure of the used lubricating oil is used to cause the periodic addition of the fresh oil to the crankcase. The frequency of the pressure strokes is set by a timer in an electronic controller, and is adjustably set to stroke at fixed time intervals to provide a cumulative quantity of fresh oil to the crankcase according to the regular recommended oil change period for the particular engine. A pair of dials on the controller enable the frequency of the pressure strokes to be adjusted. However, the piston and cylinder of the displacement unit necessarily receives both used oil and fresh oil. Therefore, the removal and make-up systems are integrated together thereby requiring a fresh oil system which may be undesirable in certain applications.
U.S. Pat. Nos. 4,421,078; 4,495,909; and to Hurner disclose similar systems for oil changing and making up during engine operation which include a control module having an adjustable impulse timer set to periodically cycle an air pressure operated oil extractor pump at a fixed time intervals to direct a predetermined amount of engine oil out of the oil pan and into the fuel tank. The pump includes a cylinder containing a movable piston defining opposed chambers and a solenoid valve operating to connect one chamber with lube oil and the opposite chamber with pressurized air such that used oil is delivered to the fuel system from only one chamber. Fresh makeup oil is pumped from an oil reservoir to the crankcase, also by air pressure, in response to a low level signal from a dipstick sensor. However, these systems require the use of pressurized air to actuate the oil changing/removing device. As a result, this system may be difficult and expensive to integrate into an engine.
Although capable of automatically changing lube oil during engine operation, the automatic oil changing systems discussed hereinabove are incapable of accurately varying and controlling oil changing in response to the actual needs of the engine that vary based on the engine operating conditions, such as fuel consumption. U.S. Pat. No. 5,7491,339 discloses an electronically controlled continuous lubricating oil replacement system which injects the used engine lubricating oil into the engine fuel system during operation based on engine operating conditions. An electronic controller is provided to vary the amount of used lube oil injected into the fuel system based on the severity of engine operation. The system maintains the quality of the engine lube oil at a level necessary to provide optimal engine protection at all engine operating conditions. This reference recognizes that the lube oil pumps disclosed in the Hurner references may be used in conjunction with the ""339 system with the pressurized lube oil being used instead of pressurized air to force the used lube oil into the fuel system. However, neither the ""339 nor the Hurner references disclose a simple, low cost system for accomplishing lube oil removal without automatic fresh oil replacement.
U.S. Pat. No. 5,676,106 discloses an oil renewal system including a single piston oil removal system without automatic fresh oil replacement including two chambers wherein used oil pressure in one chamber moves the piston to force used oil from the other chamber into a fuel system. However, oil is delivered from both chambers into the fuel system and each stroke of the piston results in oil delivery to the fuel system.
Therefore, there is a need for an engine lube oil removal system capable of effectively controlling the quantity of used lube oil removed from an engine lube oil system in a simple, inexpensive manner.
It is an object of the present invention, therefore, to overcome the disadvantages of the prior art and to provide a lube oil removal system for an engine capable of reliably, accurately and effectively controlling the rate at which lube oil is removed from the engine""s lube oil system.
It is another object of the present invention to provide an oil removal system capable of burning only the optimal quantity of lube oil in the engine""s fuel system.
It is yet another object of the present invention to provide an oil removal system which eliminates complete oil changes by avoiding oil draining and disposal so as to minimize engine down time.
Still another object of the present invention is to provide a low cost yet reliable oil removal system which allows the use of existing systems or procedures to be efficiently utilized in a cost effective manner to achieve fresh oil replacement.
Yet another object of the present invention is to provide an electronically controlled continuous oil removal system which eliminates the need to dispose of used engine oil.
Another object of the present invention is to provide an inexpensive electronically controlled continuous oil removal system which can be easily retrofit on existing engines and integrated into new engines.
Still another object of the present invention is to provide a lube oil pump system which includes a single piston and a minimum number of control valves thereby providing a compact, inexpensive and lightweight lube oil pump assembly.
These and other objects of the present invention are achieved by providing an electronically controllable lube oil removal system for an engine lube oil system comprising a removal and injection pump including a piston mounted for reciprocal movement, a first chamber positioned on one side of the piston and a second chamber mounted on a second side of the piston. The piston moves through a transfer stroke toward the first chamber and through an injection stroke toward the second chamber. A used oil circuit is provided and connected to the engine lube oil system. Also, a pump control device is provided for controlling a flow of used oil from the first chamber into the second chamber to cause movement of the piston through the transfer stroke and for controlling a flow of used oil from the engine lube oil system through the used oil circuit into the first chamber to cause movement of the piston through the injection stroke and discharge of the removed used oil from the second chamber. The removal and injection pump may include a biasing spring positioned to bias the piston toward the first chamber. A discharge circuit may be connected to the second chamber and a check valve positioned in the discharge circuit to prevent backflow into the second chamber. A transfer circuit may be used to connect the first chamber and the second chamber while a check valve may be positioned in the transfer circuit to prevent flow from the second chamber to the first chamber. The pump control means may include only one two-position, three-way valve and this valve may be solenoid operated.
The present invention is also directed to an engine comprising a lube oil system, a fuel system for supplying fuel to the engine land a removal and injection pump including a piston mounted for reciprocal movement. The removal and injection pump also includes a first chamber positioned on one side of the piston and a second chamber mounted on a second side of the piston wherein the piston is operable to move through the transfer and injection strokes. The used oil circuit and the transfer circuit mentioned above are also provided. A pump control valve device is also included which is positioned along the transfer circuit and the used oil circuit. The pump control valve device is movable into a first position blocking flow of used oil from the used oil circuit into the first chamber while permitting removed used oil flow from the first chamber to the second chamber and a second position blocking flow of used oil between the first and the second chambers while permitting flow of used oil from the used oil circuit into the first chamber causing movement of the piston through the injection stroke and discharge of used oil from the second chamber for injection into the fuel system.
The present invention is also directed to a method for removing used lube oil from an engine lube oil system, comprising the steps of providing a removal and injection pump including a piston mounted for reciprocal movement, a chamber positioned on one side of the piston and a second chamber mounted on a second side of the piston. The steps further include directing a flow of used oil from the engine lube oil system into the first chamber to form a removed quantity of used oil, directing at least a portion of the removed quantity of used oil from the first chamber into the second chamber and discharging the at least a portion of the removed quantity of used oil in the second chamber from the second chamber. Also, the step of directing a flow of used oil from the engine lube oil system into the first chamber to form a removed quantity of used oil may occur simultaneously with the step of discharging the at least a portion of the removed quantity of used oil in the second chamber from the second chamber.